1. Field of the Invention
The invention relates to a method of a global roaming service for global roaming service subscribers in third generation mobile telecommunication (IMT-2000) networks, and in particular a method of global roaming services which performs a roaming for global roaming subscribers with a VLR(Visitor Location Register)xe2x80x94GLR(Gateway Location Register)xe2x80x94GLRxe2x80x94HLR(Home network Location Register) structure between home and visitor networks, provides an environment for application services provided by the home network to be used from the visitor network, and allows the subscribers to change additional service information stored in the HLR of the home networks from the visitor networks as well while concentrically managing local subscribers who moved to visitor networks and oversees subscribers entered from other networks.
2. Description of the Related Art
In the currently provided roaming services in a plurality of third generation mobile telecommunication networks such as IMT-2000 networks which are operated by different service providers, when a terminal is moved from the home network (i.e., the network of a service provider with whom the terminal owner has made a service contract) to a visitor network (i.e., a network of a service provider having a service area where the terminal owner is currently located in the roaming), the visitor network acquires location information of the moved terminal from the home network for performing phone call service on the terminal based upon the acquired location information.
FIG. 1 shows a signal flow according to the roaming service between the third generation mobile telecommunication networks of the related art, in which a terminal MS_A has the home network A and a terminal MS_C has the home network C. Here, the terminal MS_C moves to the network A and the terminal MS_A moves to network B.
First, when the terminal MS_A moves from the home network A to the B network as a visitor network as indicated with {circle around (1)}, the moved terminal MS_A transmits a location register message to a VLR_B1 as indicated with {circle around (2)}, and the VLR_B1 stores the location register message to an area A of a GLR_B as indicated with {circle around (3)}.
Then, the GLR_B receives IMSI(Intentional Mobile Subscriber ID) parameters from the location register message registered in the area A, and interprets MCCs(Mobile Country Codes) within the parameters to recognize that the terminal MS_A is moved from the network A.
And then, the GLR_B confirms an HLR ID where subscriber information of the terminal MS_A is stored based upon subscriber number thereof, and if the detected HLR ID is xe2x80x9cHLR_A1xe2x80x9d for example, requests the HLR_A1 to transmit packet subscriber information and line subscriber information as indicated with {circle around (4)}.
When the HLR_A1 transmits the packet subscriber information and line subscriber information of the terminal MS_A to the GLR_B as indicated with {circle around (5)} on the foregoing request, the GLR_B stores the packet subscriber information and line subscriber information to xe2x80x9cAxe2x80x9d area and then transmits the corresponding packet subscriber information and line subscriber information to the VLR_B1 for storage as indicated with {circle around (6)}.
The terminal MS_A roamed via the foregoing process has the packet subscriber information and line subscriber information stored in the registered VLR_B1 so that the terminal MS_A can be provided with a normal phone call service in the visitor network (network B) after that.
In particular, to perform the foregoing operations, a GLR comprised in one third generation mobile telecommunication network is associated with all HLRs comprised in other third generation mobile telecommunication networks for providing a roaming service so that the GLR is downloaded with the subscriber information from the HLR in the home network of the roamed subscriber.
However, the foregoing method for providing roaming services has problems in that signal traffic is complicated since the GLR of one third generation telecommunication network should be associated with the HLRs of all mobile telecommunication networks that can be roamed, and the subscriber information stored in the HLR of the home network can be exposed incurring security problems because all the HLRs of the home network are opened by the GLR of other networks established in the visitor network.
Also, in the first roaming to the visitor network, the GLR of the visitor network is required to be processed in order to detect the HLR stored with the subscriber information of the roaming terminal from the plurality of HLRs comprised in the home network of the roaming terminal for the first location register procedure and first subscriber information download regarding the roaming terminal. Furthermore, when the visitor network and home network are established with different next generation mobile telecommunication network systems, the visitor network GLR and the home network HLR should have an MAP(Mobile Application Part) conversion. When the visitor network GLR does not have MAP conversion protocols, an IWF(Inter Working Function) is required between the GLR and HLR.
The invention is proposed to solve the foregoing problems of the related art, and it is therefore an object of the invention to provide a method of roaming services for global roaming subscribers in third generation mobile telecommunication networks, in which information stored in a HLR can be downloaded to a visitor network GLR via a home network GLR of a roamed terminal when the terminal is moved into the visitor network.
Also, it is another object of the invention to provide a method of roaming services in which a USSD(Unstructured Supplementary Service Data) handler is downloaded to the visitor network GLR so that the roamed terminal can be provided with the same application services in the visitor network as in the home network, and additional service information stored in the home network HLR can be changed in the visitor network also when MMI(Man Machine Interface) commands including service codes, i.e., codes for discriminating services and service information, i.e., service information desired to be changed are directly inputted from the corresponding terminal so that the subscribers can change their additional service information everywhere.
To obtain the foregoing objects of the invention, there is provided a method of roaming services for global roaming subscribers in third generation mobile telecommunication networks having a GLR(Gateway Location Register), HLR(Home network Location Register) and VLR(Visitor Location Register) in which the GLR is stored with subscriber information about a terminal, which is roamed from the home network to a visitor network, to provide the roamed terminal with the same services in the visitor network as in the home network, wherein upon transmitting in the roamed terminal a location register message, the GLR of the visitor network requests location register and the subscriber information download to the HLR of the home network via the GLR of the home network; and is downloaded with the subscriber information stored in the home network HLR to manage the roamed terminal.
To obtain the foregoing objects of the invention, there is provided another method of roaming services for global roaming subscribers in third generation mobile telecommunication networks having a GLR, HLR and VLR in which the GLR and VLR are stored with subscriber information about a terminal, which is roamed from the home network to a visitor network, to provide the roamed terminal with same services in the visitor network as in the home network, the method comprising the steps of: inputting in the roaming completed terminal an MMI command according to additional service changes to transmit the command via the GLR of the visitor network to the GLR of the home network; changing in the home network GLR additional service information stored in the HLR of the home network in response to the MMI command; transmitting in the HLR the changed additional service information to the home network GLR; storing in the home network GLR and transmitting the additional service information to the visitor network GLR; and storing in the visitor network GLR and transmitting the additional service information to the VLR where the roamed terminal is currently registered, whereby the roamed terminal can change the additional service information stored in the home network HLR.
To obtain the foregoing objects of the invention, there is provided further method of roaming services for global roaming subscribers in third generation mobile telecommunication networks having a GLR, HLR and VLR in which the GLR and VLR are stored with subscriber information about a terminal, which is roamed from the home network to a visitor network, to provide the roamed terminal with same services in the visitor network as in the home network, wherein programs for supporting application services or intelligent network services provided in the home network are downloaded to the GLR of the visitor network via the GLR of the home network, whereby the roaming completed terminal can be provided with application services or intelligent network services according to the operation of the downloaded programs in the visitor network as well.